(a) Field of the Invention
The present invention relates to a vehicle hood including a hood outer panel and a hood reinforcement arranged at the underside of the hood outer panel. In particular, it relates to an improvement in bending of the vehicle hood in a frontal crash.
(b) Description of Related Art
For improvements in safety of pedestrians and impact absorption of vehicles, there have been known vehicle hoods including a hood outer panel which is configured to bend surely at a predetermined position in a frontal crash.
Such vehicle hoods, however, have a problem. If the hood outer panel is formed with a bulge protruding upward beyond the other part of the hood outer panel for providing space for mounting engine auxiliaries, the hood outer panel is hindered from bending at a predetermined position in a frontal crash because the bulge is highly rigid than the other part and not easily deformed.
Accordingly, for example, Japanese Unexamined Patent Publication S59-176166 discloses forming the bulge as a separated part from the hood outer panel so that the bulge comes off the hood outer panel in a frontal crash.
Further, in conventional vehicle hoods, a lattice-formed frame (corresponding to a hood reinforcement) is provided at the underside of the hood outer panel. Since the lattice-formed frame is highly rigid at the lattice points, a pedestrian is greatly damaged if he/she is bumped against the lattice points. Accordingly, in response to the need for the protection of pedestrians in recent years, Japanese Unexamined Patent Publication No. 2003-191865 discloses a hood reinforcement which is panel-shaped to correspond to the shape of the hood outer panel.
However, since the former conventional vehicle hood includes the bulge separated from the hood outer panel, parts count increases, resulting in an increase in cost. If the bulge is integrally formed with the hood outer panel for design purposes, the bulge cannot come off the hood outer panel.
In the latter conventional vehicle hood, the state of bonding between the panel-shaped hood reinforcement and the hood outer panel becomes substantially uniform. This brings about dispersion of load of a frontal crash, and therefore the hood outer panel does not easily bend along a bend line at a predetermined position.
Moreover, if the hood outer panel and the hood reinforcement each have a convex form at the front ends thereof for design purposes when viewed in plan, the front end of the hood is reduced in rigidity. Therefore, in a frontal crash, the front end of the hood is deformed easily and the load of the crash is not smoothly transferred rearward. As a result, a bend line cannot be formed at a predetermined position.